The inventive concept relates to a semiconductor memory device and a related read method. More particularly, the inventive concept relates to a multi-level cell (MLC) flash memory device and read method providing reduced read time.
Flash memory is a form of non-volatile memory capable of retaining stored data in the absence of applied power. Flash memory is widely used in portable electronic devices, such as cellular phones, personal digital assistants (PDA), digital cameras, portable game consoles, MPEG-1 Audio Layer 3 (MP3) players, and the like, to store not only payload data, but also programming code. Flash memory is also widely used in various consumer electronics, such as high definition televisions (HDTV), Digital Versatile Discs (DVD), routers, Global Positioning Systems (GPS), etc.
Flash memory may be categorized according to the type of memory cells used to implement the constituent memory cell array. Either single-level cell (SLC) storing one data bit per memory cell, or MLC storing at least two data bits per memory cell may be used. The general expansion in the data storage capacity of flash memory as well as the increasing use of MLC has given rise to concern over the length of time required to access (“read”) stored data. Indeed, “read time” has become an increasingly important memory system performance characteristic as flash memory is used to store different type of data. Thus, ongoing research is directed to not only ensuring data reliability in flash memory, but also reducing the time required to program data to and read data from MLC flash memory.